Chernobyl Diaries is afflicted with a fatal flaw that damages many horror films: after a better-than-average setup and a promising first half, everything falls apart. The filmmakers spend so much time figuring out the hook and establishing the atmosphere that they forget the keys necessary to ensure sustained audience involvement, including a compelling middle section and a satisfying (although not necessarily upbeat) conclusion. Chernobyl Diaries is so derivative that hardly a moment goes by without triggering a strong sense of déjà vu. This, in and of itself, is not necessarily a bad thing, but the movie fails to do much that's interesting with all the material it pilfers. Even lazy horror fans will notice similarities in style and/or story to The Hills Have Eyes, The Blair Witch Project, and The Ruins. Die-hard aficionados will be able to add at least another dozen titles to that list.

Chernobyl Diaries focuses on the misadventures of a group of six tourists who unwisely decide to embark upon an "extreme tour" of the Ukrainian ghost city of Prypiat, the former population center of the families of workers at the Chernobyl Nuclear Power Plant. Prypiat was evacuated shortly after the April 1986 disaster at the plant, and has remained unpopulated since, existing as it does within the so-called "Zone of Alienation." In the real world, tour groups are now allowed within Prypiat (assuming they have the necessary paperwork), so there is some basis in fact for the back story. In addition, director Bradley Parker did some of his filming on-site in Prypiat, which contributes greatly to the sense of verisimilitude and the eerie feeling that permeates the strong first 30 minutes.

The tour group is comprised of four Americans - Paul (Jonathan Sadowski) and his brother, Chris (Jesse McCartney), Chris' long-time girlfriend, Natalie (Olivia Taylor Dudley), and Natalie's best friend, Amanda (Devin Kelley) - and two Australians - couple Michael (Nathan Phillips) and Zoe (Ingrid Bolso Berdal). They are led by guide Uri (Dimitri Diatchenko), an ex-Special Forces tough guy (who, based on an undeveloped non-verbal moment, may have some history associated with Prypiat). Things go okay for most of the day, which includes wandering through abandoned buildings, standing on a balcony with a view of the decommissioned reactor site, and visiting the infamous Ferris Wheel. Unfortunately, with dusk approaching, they discover that the van won't start. At the same time, there are disquieting signs that Prypiat might not be as abandoned as advertised. So begins a tense night in a cramped vehicle.

The movie starts to fall apart during the middle of the night. We quickly come to the realization that, for the betterment of the human species, all seven of these people must die. As stupid as they are, they cannot be permitted to reproduce and pass on their DNA to another generation. Admittedly, it's an accepted staple of the genre that smart characters occasionally do inexplicably dumb things, but Chernobyl Diaries takes this to extremes. The movie is built upon a foundation of idiocy. In any given circumstance, figure out what the most moronic course of action would be, and chances are that's the way things go. The less said about the "surprise" ending, the better. It doesn't make a lot of sense but, by then, such a minor concern no longer matters.

Parker, making his feature debut from a script developed by Paranormal Activity mastermind Oren Peli, doesn't use Peli's first-person, found footage approach to filming, but he does the next worst thing. He plants a hand-held camera in the midst of the group, opting to make the viewer an unseen participant in the "action," and jiggles things enough that motion sickness will be the inevitable result for some sensitive viewers. When running is involved, we get the Blair Witch effect of the camera shaking so badly that the images become incoherent. There's a lot of running during the second half as the characters are picked off one-by-one. This allows viewers to play the popular bad horror movie guessing game of "Predict Who Dies Next." The prize should be a pass to skip the next movie with Peli's name attached.

It's pointless discussing the talent (or lack thereof) of the various actors since none is given a legitimate character to play. The banter - what little there is of it - is unenlightening. The girls are attractive, the guys represent various "guy types," and Prypiat consistently steals scenes from the humans. There's something genuinely spooky about seeing all those abandoned high-rise buildings and knowing they're real. This isn't some small town that time forgot. This is a city of 50,000 with a strong Marie Celeste vibe. It's inconceivable that the filmmakers have failed to milk this for all it's worth.

The "horror" aspect of Chernobyl Diaries involves cannibalistic radiation-mutated human beings (or at least I think that's what they are) that spend an inordinate amount of time lurking before finally deciding to attack en masse. As horror movie bad guys go, these are near the bottom of the pack. They're not all that interesting and, to be frank, not all that scary. Near the 30-minute mark, Chernobyl Diaries can be credited for doing a good job establishing the situation and embarking upon a gradual escalation of tension. It then proceeds to waste these assets and generate an hour of frequent watch-checking. (Is the second-hand still moving?) Those with low standards for horror movies may be diverted by Chernobyl Diaries. Others will see this as a wasted opportunity and wonder why, based on the accumulated evidence, Peli is so highly regarded.